Anhydrous antiperspirant compositions

ABSTRACT

Anhydrous antiperspirant stick or soft solid composition comprising an antiperspirant active system, thickening agent, and non-aqueous carrier oil, characterised in that the particulate antiperspirant active system comprises an aluminium sesequichlorohydrate of formula Al 2 (OH) 4.4 Cl 1.6  to Al 2 (OH) 4.9 Cl 1.1  activated with a water soluble calcium salt.

This application is a national phase filing under 35 USC 371 ofInternational Application No. PCT/EP2015/074528, filed on Apr. 20, 2017,which claims priority from European Patent Application No. 14190531.5filed Oct. 27, 2014, the contents of which are incorporated herein intheir entirety for all purposes.

The present invention is concerned with antiperspirant compositions andwith methods of making the same. It is particularly concerned withanhydrous stick and soft solid compositions comprising aluminiumsesquichlorohydrate antiperspirant actives.

Certain activated basic aluminium chloride (herein BAC) actives arecommercially available and their preparation and use are disclosed innumerous publications.

Traditionally, activated BAC samples have been prepared by prolongedheating of BAC solutions followed by spray drying; see, for example,U.S. Pat. No. 4,359,456 (Gosling). The samples prepared by this methodneeded to be formulated into essentially anhydrous compositions in orderfor the antiperspirant to maintain its high activity.

Activated BAC samples have also been prepared using water solublecalcium acids, particularly with a further adjunct such as an aminoacid, hydroxyl acid, or betaine. Some of these samples could beformulated into aqueous compositions without the antiperspirant losingall of its enhanced activity.

EP 1,104,282 (Gillette) discloses a means of producing activated BACsamples using a water soluble calcium salt and an amino acid or ahydroxy acid.

U.S. Pat. No. 6,911,195 (Gillette) discloses water-in-oil emulsion gelscomprising aluminium-zirconium antiperspirant salts activated usingcalcium ions.

U.S. Pat. No. 5,955,065 (Gillette) discloses anhydrous suspensionformulations comprising particulate BAC and aluminium-zirconiumantiperspirant salts activated using calcium ions.

U.S. Pat. No. 6,942,850 (Gillette) discloses aqueous alcoholiccomposition comprising aluminium-zirconium antiperspirant saltsactivated using calcium ions.

WO 2009/044381 (P&G) discloses water-in-oil emulsion sticks comprisingBAC and aluminium-zirconium antiperspirant salts activated using calciumions.

U.S. Pat. No. 7,704,531 (Colgate) discloses compositions comprising anactive system made from combining an aluminium or aluminium-zirconiumsalt, a calcium salt, and a betaine.

US 2011/0038823 (Dial/Henkel) discloses water-in-oil emulsion stickscomprising an antiperspirant active prepared by combining BAC, calciumchloride and glycine.

US 2007/196303, US 2007/0020211, WO 2008/063188, US 2008/0131354 andU.S. Pat. No. 7,087,220 (Summit and Reheis) each describe methods ofmaking calcium-activated antiperspirant salts.

WO 2009/075678, WO 2009/076592, WO 2011/016807, WO 2012/060817, WO2012/061280, WO 2012/148480 and WO 2012/148481 (Colgate) disclose themanufacture of activated antiperspirant salts by neutralisation ofaluminium chloride with calcium hydroxide in the presence of glycine.

The present invention is particularly concerned with BAC compositionscomprising aluminium sesquichlorohydrate (herein ASCH) of chemicalformula Al₂(OH)_(4.4)Cl_(1.6) to Al₂(OH)_(4.9)Cl_(1.1). This material iscommercially available, but its formulation and use described herein arenew and deliver unexpected benefits.

In a first aspect of the present invention, there is provided ananhydrous antiperspirant stick or soft solid composition comprising anantiperspirant active system, thickening agent, and non-aqueous carrieroil, characterised in that the particulate antiperspirant active systemcomprises an aluminium sesquichlorohydrate of formulaAl₂(OH)_(4.4)Cl_(1.6) to Al₂(OH)_(4.9)Cl_(1.1) activated with a watersoluble calcium salt.

In a second aspect of the present invention, there is provided a methodof manufacture of a composition according to the first aspect of theinvention.

In a third aspect of the present invention, there is provided a methodof attaining an antiperspirant benefit comprising the topicalapplication to the surface of the human body of a composition accordingto the first aspect of the invention.

The choice of BAC salt used is critical to the success of the presentinvention. We have found that surprisingly good results are found onusing BAC salts commonly referred to as aluminium sesquichlorohydrate(herein ASCH) having the chemical formula Al₂(OH)_(4.4)Cl_(1.6) toAl₂(OH)_(4.9)Cl_(1.1). Most commercial ASCH samples are of chemicalformula Al₂(OH)_(4.7)Cl_(1.3) to Al₂(OH)_(4.9)Cl_(1.1). and it ispreferred to use ASCH salts of this formula.

The surprisingly good results referred to in the above paragraph includesurprisingly good antiperspirancy performance. In addition, compositionsprepared according to the present invention have remarkable storagestability, maintaining their good performance for many months.

The BAC salt used in the present invention has aluminium to chloridemolar ratio of from 1.25:1 to 1.82:1 and preferably 1.54:1 to 1.82:1.

The present invention involves the “activation” of ASCH by a watersoluble calcium salt and preferably an amino acid.

In order for the ASCH to become activated, it is important to havesufficient calcium present relative to the amount of aluminium present.The molar ratio of calcium to aluminium is typically at least 1:40,preferably at least 1:30 and more preferably at least 1:20. It is notadvantageous to have the calcium concentration in excess of thealuminium concentration, indeed it is preferred that the calciumconcentration is no more than half that of the aluminium concentrationand more preferred that it is no more than a fifth of saidconcentration. For the preferred molar ratios of calcium to aluminium ofat least 1:40 and at least 1:20, it is independently preferred that thisratio is no greater than 1:2 and more preferred that it is no greaterthan 1:5.

In particularly preferred embodiments, the molar ratio of calcium toaluminium is at least 1:15 and preferably no greater than 1:5 and inespecially preferred embodiments it is at least 1:10 and preferably nogreater than 1:5.

A preferred water soluble calcium salt for use in the present inventionis calcium chloride.

Herein, references to molar amounts and ratios of “aluminium” arecalculated on the basis of mono-nuclear aluminium, but include aluminiumpresent in poly-nuclear species; indeed, most of the aluminium in thesalts of relevance is present in poly-nuclear species.

In preferred embodiments, an amino acid is also used to activate theASCH. The molar ratio of amino acid to aluminium is preferably at least1:20, more preferably at least 1:10 and most preferably at least 1:5. Itis not advantageous to have the amino acid concentration in excess ofthe aluminium concentration; hence, the molar amino acid to aluminium ispreferably from 1:20 to 1:1, more preferably from 1:10 to 1:1 and mostpreferably from 1:5 to 1:1.

In particularly preferred embodiments, the molar ratio of amino acid toaluminium is at least 1:4 and preferably no greater than 1:1 and inespecially preferred embodiments it is at least 1:3 and preferably nogreater than 1:1.

The presence of both calcium and amino acid is highly preferred for thesuccess of the present invention. In preferred embodiments, the molarratio of calcium to aluminium is at least 1:40 and the molar ratio ofamino acid to aluminium is at least 1:20. In further preferredembodiments the molar ratio of calcium to aluminium is at least 1:20 andthe molar ratio of amino acid to aluminium is at least 1:10. Inparticularly preferred embodiments the molar ratio of calcium toaluminium is from 1:20 to 1:5 and the molar ratio of amino acid toaluminium is from 1:10 to 1:1.

In certain especially preferred embodiments, the molar ratio of calciumto aluminium is from 1:15 to 1:5 and the molar ratio of amino acid toaluminium is from 1:4 to 1:1. In these especially preferred embodiments,exemplary performance in is obtained when the molar ratio of calcium toaluminium is from 1:10 to 1:5 and the molar ratio of amino acid toaluminium is from 1:3 to 1:1.

The above indicated preferences for calcium to aluminium molar ratioand/or amino acid to aluminium molar ratio lead to compositions ofhigher Band III content (vide infra) and, in general, higherantiperspirancy performance. It will be noted that higher Band IIIcontent is generally indicative of higher antiperspirancy performance.

The activation process generally produces a mixture of aluminium specieshaving a relatively high content of what is commonly termed Band IIImaterial, as determined by SEC (Size Exclusion Chromatography) analysis.The SEC technique employed is well known in the art and is described infurther detail in U.S. Pat. No. 4,359,456 (Gosling). The SEC bandcommonly referred to as Band III is designated as “Peak 4” in EP1,104,282 B1 by Gillette.

Herein, “Band III content” refers to the integrated area in the Band IIIregion of the SEC chromatograph relative to the total integrated area inall of the regions corresponding to aluminium species; that is to say,Bands I, II, III, and IV.

In preferred embodiments of the invention, the aluminiumsesquichlorohydrate in the particulate antiperspirant active system hasa Band III content of at least 40%; in particularly preferredembodiments, the Band III content of the aluminium sesquichlorohydrateis at least 55%.

In the activation process and method of manufacture described herein, itis preferred that the activation mixture is heated sufficiently for theBand III content of the aluminium species to become at least 40% andmore preferably at least 55%.

The method of manufacture described herein involves the production anaqueous solution of an activated antiperspirant salt. Such solutions arethen dried, typically by spray-drying and the resulting powderincorporated in a composition according to the invention.

Hence, the particulate antiperspirant active used in the presentinvention may typically be considered to be a co-spray-dried mixture of(i) aluminium sesquichlorohydrate of formula Al₂(OH)_(4.4)Cl_(1.6) toAl₂(OH)_(4.9)Cl_(1.1) activated by calcium chloride and (ii) the calciumchloride used to achieve said activation. Preferably, the antiperspirantactive may be considered to be a co-spray-dried mixture of (i) aluminiumsesquichlorohydrate of formula Al₂(OH)_(4.4)Cl_(1.6) toAl₂(OH)_(4.9)Cl_(1.1) activated by calcium chloride and an amino acidand (ii) the calcium chloride and amino acid used to achieve saidactivation.

The method of manufacture typically involves a solution of aluminiumsesquichlorohydrate of formula Al₂(OH)_(4.4)Cl_(1.6) toAl₂(OH)_(4.9)Cl_(1.1) being heated with a water soluble calcium salt toachieve a Band III content of at least 50% before being spray dried togive a powder which is subsequently formulated with a suspending agent,carrier oil and liquefied propellant gas.

In a preferred method of manufacture as described in the aboveparagraph, the aluminium sesquichlorohydrate is also heated with anamino acid. In a particularly preferred aspect of this method, thealuminium sesquichlorohydrate is heated to achieve a Band III content ofat least 60%.

The spray-dried powder produced from the aqueous solution of anactivated antiperspirant salt as described above is the particulateantiperspirant active system comprising a water soluble calcium salt andan aluminium sesquichlorohydrate of formula Al₂(OH)_(4.4)Cl_(1.6) toAl₂(OH)_(4.9)Cl_(1.1) as described in the first aspect of the invention.

The particulate antiperspirant active system preferably has a meanparticle size (D50) of from 2 to 30 microns, more preferably from 2 to20 microns, and most preferably from 2.5 to 10 microns. Suchcompositions have been found to give surprisingly good antiperspirancyperformance and also have good sensory properties.

Herein, mean (D50) particle sizes may be measured using (laser) lightscattering techniques, for example using a Mastersizer instrument,obtainable from Malvern Instruments. Such instruments are set to producea volume plot and a lens is selected in accordance with the makersinstructions to accommodate the expected particle size distribution, (orvarious lenses can be tested until the best lens is identified).Measurements are made by methods known in the art.

The particulate antiperspirant active system is preferably spray-driedusing rotary atomisation.

The compositions of the present invention are anhydrous, having lessthan 2% by weight of free water, preferably less than 1% by weight offree water, more preferably less than 0.5% free water and mostpreferably less than 0.1% free water.

Herein, “free water” excludes any water of hydration associated with theantiperspirant salt or other solid component added to a particularcomposition, but includes all other water present.

Herein, references to amounts of components such as “carrier oil” or“thickening agent” relate to the total amount of such components presentin the composition.

Other non-essential components may also be including in compositionsaccording to the invention.

Herein, amounts and concentrations of ingredients are percentages byweight of the total composition, unless otherwise indicated and ratiosare ratios by weight, unless otherwise indicated.

Herein, unless the context demands otherwise, all weights, % s, andother numbers can be qualified by the term “about”.

Compositions according to the present invention have a certain hardnessin order for them to be used a sticks or soft solids.

The “hardness” of stick and soft solid compositions refers to the depth,in millimetres, that a cone penetrates into a test specimen under fixedconditions, as determined in accordance with the procedures of ASTMMethod D217-48, incorporated herein by reference, using a PetrotestPNR10 Penetrometer (or equivalent), equipped with an ASTMD2884 plunger(Petrotest Cat. #18-0081 or equivalent, weight=47.5 g) and a 2.5 galuminium cone, 20° angle with a base diameter of 10 mm, whereinhardness values are reported as an average of 6 replicate measurements.

Compositions according to the present invention typically have ahardness of less than 30 mm, preferably less than 25 mm and morepreferably less than 20 mm.

Soft solid compositions according to the present invention typicallyhave a hardness value of from 5 to 25 mm, more particularly from 10 to20 mm.

Stick compositions according to the present invention typically have ahardness value of less 20 mm and preferably less than 15 mm.Particularly preferred stick compositions have a hardness of from 7.5 to12.5 mm.

An essential component of compositions of the invention is carrier oil.In preferred embodiments, this may also be a masking oil, serving thepurpose of reducing visible deposits when the composition accidentallycomes into contact with clothing, for example.

Herein, the terms “oil” and signifies a water-insoluble organic materialthat is liquid at 20° C. Any material having a solubility of less than0.1 g/100 g at 20° C. is considered to be insoluble.

A preferred optional component for use in accordance with the presentinvention is a fragrance oil, sometimes alternatively called a perfumeoil. The fragrance oil may comprise a single fragrance or component morecommonly a plurality of fragrance components. Herein, fragrance oilsimpart an odour, preferably a pleasant odour, to the composition.Preferably, the fragrance oil imparts a pleasant odour to the surface ofthe human body the composition is applied to the same.

The amount of fragrance oil in the composition is commonly up to 3%advantageously is at least 0.5% and particularly from 0.8% to 2%.

The total amount of carrier oil in the composition may be from 5% to95%, but is preferably from 10 to 90% and more preferably from 15 to85%.

As fragrance oil may also serve as carrier oil, it should also beincluded as carrier oil in calculating the amount of this lattercomponent present in the composition.

The carrier oil may be selected from any of those known in the art,although hydrophobic carrier oils are preferred.

A preferred class of carrier oil are silicone oils, that is to say,liquid polyorganosiloxanes. Such materials may be cyclic or linear,examples include Dow Corning silicone fluids 344, 345, 244, 245, 246,556, and the 200 series; Union Carbide Corporation Silicones 7207 and7158; and General Electric silicone SF1202.

Suitable carrier oils can be selected from alkyl ether oils having aboiling point of above 100° C. and especially above 150° C., includingpolyalkyleneglycol alkyl ethers. Such ethers desirably comprise between10 and 20 ethylene glycol or propylene glycol units and the alkyl groupcommonly contains from 4 to 20 carbon atoms. The preferred ether oilsinclude polypropylene glycol alkyl ethers such as PPG-14-butylether andPPG-15-stearyl ether.

Suitable carrier oils can include one or more triglyceride oils. Thetriglyceride oils commonly comprise the alkyl residues of aliphatic C₇to C₂₀ alcohols, the total number of carbon atoms being selected inconjunction with the extent of olefinic unsaturation and/or branching toenable the triglyceride to be liquid at 20° C. One example is jojobaoil. Particularly preferably, in the triglyceride oil the alkyl residuesare linear C₁₈ groups having one, two or three olefinic degrees ofunsaturation, two or three being optionally conjugated, many of whichare extractable from plants (or their synthetic analogues), includingtriglycerides of oleic acid, linoleic acid, conjugated linoleic acids,linolenic acid, petroselenic acid, ricinoleic acid, linolenelaidic acid,trans 7-octadecenoic acid, parinaric acid, pinolenic acid, punicic acid,petroselenic acid and stearidonic acid.

Suitable carrier oils can include those derived from unsaturated C₁₈acids, including coriander seed oil, impatiens balsimina seed oil,parinarium laurinarium kernel fat oil, sabastiana brasilinensis seedoil, dehydrated castor seed oil, borage seed oil, evening primrose oil,aquilegia vulgaris oil, sunflower (seed) oil and safflower oil. Othersuitable oils are obtainable from hemp, and maize corn oil. Anespecially preferred oil by virtue of its characteristics is sunflower(seed) oil.

Further suitable carrier oils, that can also be emollient oils, comprisealkyl or alkyl-aryl ester oils having a boiling point of above 150° C.(and a melting point of below 20° C.). Such ester oils include oilscontaining one or two alkyl groups of 12 to 24 carbon atoms length,including isopropyl myristate, isopropyl palmitate and myristylpalmitate. Other non-volatile ester oils include alkyl or aryl benzoatessuch C₁₂₋₁₅ alkyl benzoate, for example Finsolv TN™ or Finsolv Sun™.

A further class of suitable carrier oils comprises non-volatiledimethicones, often comprising phenyl or diphenylene substitution, forexample Dow Corning 200 350 cps or Dow Corning 556.

A further essential component of compositions of the invention is athickening agent, sometimes alternatively referred to as a gelling agentor gellant. Such agents increase the viscosity of or solidify thecarrier oil in which the particulate antiperspirant active is typicallysuspended.

The thickening agent may be selected from any of those known in the art.Often, the thickening agent includes a wax. Waxes typically areconsidered to melt at above 40° C. and particularly between 55 and 95°C. Waxes can include ester waxes, including C12 to C24 linear fattyalcohols, waxes obtained from animals or plants, often afterhydrogenation, silicone elastomers and silicone waxes. The thickeningagent can comprise a mixture of particulate thickening agents, a mixtureof waxes or a mixture of both types of material.

The proportion of thickening agent thickening agents is often selectedin the range of from 1:30 to 1:12.5 parts per part by weight of carrieroil.

The thickening agents used in compositions according to the invention,and especially stick compositions according to the invention, arepreferably selected from fibre-forming non-polymeric gelling agents andwaxes, optionally supplemented by particulate silica and/or anoil-soluble polymeric thickening agent.

Waxes employed herein as thickening agents are often selected fromhydrocarbons, linear fatty alcohols, silicone polymers, esters of fattyacids or mixtures containing such compounds along with a minority (lessthan 50% w/w and often less than 20% w/w) of other compounds. Naturallyoccurring waxes are often mixtures of compounds which include asubstantial proportion of fatty esters.

Examples of hydrocarbon waxes include paraffin wax, ozakerite,microcrystalline wax and polyethylene wax, the last named desirablyhaving an average molecular weight of from 300 to 600 and advantageouslyfrom 350 to 525.

Linear fatty alcohols commonly contain from 14 to 40 carbon atoms andoften from 16 to 24. Preferred thickening agents of this class arestearyl alcohol and behenyl alcohol, with stearyl alcohol beingespecially preferred.

Examples of ester waxes include esters of C₁₆-C₂₂ fatty acids withglycerol or ethylene glycol, which can be isolated from natural productsor more conveniently synthesised from the respective aliphatic alcoholand carboxylic acid.

Examples of natural waxes include beeswax, wool wax and spermaceti waxof animal origin, and caster wax, jojoba wax, camauba wax and candelillawax which are of vegetable origin. Montan wax, which is an example ofmineral wax, includes non-glyceride esters of carboxylic acids,hydrocarbons and other constituents.

Further waxes employable herein comprise silicone polymer waxes,including waxes which satisfy the empirical formula:

R—(SiMe₂-O—)_(x)-SiMe₂R

in which x is at least 10, preferably 10 to 50 and R represents an alkylgroup containing at least 20 carbons, preferably 25 to 40 carbons, andparticularly having an average linear chain length of at least 30carbons.

Other silicone waxes comprise copolymers of dimethicone andalkyloxymethicone, satisfying the general formula:—

Y—(SiMe₂-O—)_(y)(Si[OR′]Me-O—)_(z)—Y′

in which Y represents SiMe₂-O, Y′SiMe₂, R′ an alkyl of at least 15carbons preferably 18 to 22 such as stearyl, y and z are both integers,totaling preferably from 10 to 50.

Waxes useful in the present invention will generally be those found tothicken cylcomethicone, when dissolved therein at a concentration of 5to 15% by weight.

Fibre-forming thickening agents are dissolved in the carrier oil atelevated temperature and on cooling precipitate out to form a network ofvery thin strands that structure, i.e. thicken, the carrier oil. Oneparticularly effective category comprises N-acyl aminoacid amides and inparticular linear and branched N-acyl glutamic acid dialkylamides, suchas in particular N-lauroyl glutamic acid di n-butylamide andN-ethylhexanoyl glutamic acid di n-butylamide and especially mixturesthereof. Such amido gellants can be employed in anhydrous compositionsaccording to the present invention, if desired, with 12-hydroxystearicacid.

Other amido SMGAs include 12-hydroxystearic acid amides, and amidederivatives of di and tribasic carboxylic acids as set forth in WO98/27954, including notably alkyl N,N′dialkyl succinamides.

Further suitable amido-containing thickening agents are described inU.S. Pat. Nos. 6,410,003, 7,332,153, 6,410,001. U.S. Pat. Nos.6,321,841, and 6,248,312.

The thickening agent is typically employed in the composition at aconcentration of from 1.5 to 30%. When a fibre-forming thickening agentis employed, its concentration is typically in the range of from 1.5 to15%. When a wax is employed, its concentration is usually selected inthe range of from 10 to 30%, and particularly from 12 to 24% w/w.

Some highly desirable compositions comprise in combination a firstthickening agent with a second thickening agent.

One category of oil-soluble polymer thickening agent which has beenfound suitable is a polysaccharide esterified with a mono-carboxylicacid containing at least 12 carbon atoms, and preferably a dextrin fattyacid ester such as dextrin palmitate or dextrin stearate. Commercialproducts are available under the trade mark Rheopearl.

A second category of polymer thickening agent comprises polyamides forexample those discussed in U.S. Pat. No. 5,500,209 or 6,353,076.

A third category of thickening agent comprises block copolymers ofstyrene with ethylene propylene and/or butylene available under thetrade name KRATON, and particularly styrene ethylene/butylene styrenelinear block copolymers. A related category of thickening polymercomprises polymers of alpha methylstyrene and styrene, such as thoseunder the trade name KRISTALEX, eg KRISTALEX F85 having a mean molecularweight of approximately 1200. Yet another thickening polymer comprisesalkyl substituted galactomannan available under the trade name N-HANCEAG.

A still further class of thickening polymers co-polymers of vinylpyrrolidone with polyethylene containing at least 25 methylene units,such as triacontanyl polyvinylpyrrolidone, under the trade name AntaronWP-660.

Such thickening polymer is often employed in a weight ratio to the oilblend that is selected in the range of from 1:30 to 1:5, taking intoaccount the hardness of the soft solid that is desired, the inherentability of the chosen polymer to increase viscosity and the presence orotherwise of an additional thickening agent.

A further class of material which is well suited to forming orcontributing to the formation of soft solid compositions comprisessilicone elastomers. Commonly, the elastomer is non-emulsifying andespecially is a dimethicone/vinyldimethicone cross polymer. Suchmaterials commonly supplied as a dispersion of the active material incyclomethicone fluid or a non-volatile oil, typically at a concentrationin the region of 10 to 20% by weight. Such elastomers are desirablypresent at a concentration of from 1 to 10% by weight of thecomposition.

A thickening agent especially well suited to forming or contributing tothe formation of a soft solid composition comprises particulate silicaand especially fumed silica. It is desirable to include at least 2% andespecially at least 2.5% by weight of the silica in the composition,such as in the range of up to 10% by weight.

Other components that may be included in compositions according to theinvention including those described in the following paragraphs.

Wash-off agents may be included, often in an amount of up to 10%, toassist in the removal of the formulation from skin or clothing. Suchwash-off agents are typically non-ionic surfactants such as esters orethers containing a C₈ to C₂₂ alkyl moiety and a hydrophilic moietycomprising a polyoxyalkylene group (POE or POP).

Skin feel improvers (e.g. talc or finely divided high molecular weightpolyethylene), may be included, typically in an amount from 1 up to 10%.

Skin moisturisers, such as glycerol or polyethylene glycol (e.g. mol.wt. 200 to 600) may be included, typically in an amount of up to 5%.

Skin benefit agents, such as allantoin or lipids, may be included,typically in an amount of up to 5%.

A highly preferred optional component is a preservative, such as ethylor methyl parabens or BHT (butyl hydroxy toluene), typically in anamount of from 0.01 to 0.1%.

Fragrance (vide supra) is also a highly optional component. Fragrancemay be present as free oils or it may be present in encapsulated form.

EXAMPLES

In the following examples, all percentages are by weight, unlessotherwise indicated.

The ASCH used was approximately 80% anhydrous ASCH solids (and 20%water) and was obtained from Summit as Reach 301.

The ASCH used was activated with calcium chloride and glycine andtreated as follows. 30 parts of Reach 301 powder, 4.0 parts calciumchloride dihydrate and 9.4 parts glycine were combined with 56.6 partswater. 60 L of this solution was heated at 85° C. and then maintained atthis temperature for 5 hours in a corrosion resistant 70 L vessel.

The resulting solution was spray-dried using a large scale spray dryer(inlet temperature 290+/−5°, outlet temperature 117+/−2°, rotaryatomisation).

The particulate AASCH obtained from the above process had a mean (D50)particle size of 27 microns, a Band III content of 66%, and a ratio ofBand II to Band III of 1:7.13. It comprised 19.3% Al, 2.8% Ca, and 26.0%glycine. This powder was jet milled to give a mean (D50) particle sizeof 4.3 microns. The milling resulted in an increase in the water contentof the powder of from 3.3% to 7.5%.

The powder resulting from the above processes was formulated with theother components indicated in Table 1 by methods known in the art togive Examples 1 to 4, varying only in the amount of AASCH employed.

Comparative Example A was also prepared by methods known in art, using acommercially available activated zirconium aluminium glycinate (AZAG)antiperspirant active (Reach 908, ex Summit) at 25%, i.e. equivalent tothe AASCH level used in Example 2.

TABLE 1 Examples 1 to 4 and Comparative Example A Component ExampleChemical name Trade name 1 2 3 4 A AASCH¹ 30.0 25.0 17.5 10.0 — AZAGReach 908 — — — — 25.0 Cyclomethicone DC 245 24.75 29.75 37.25 44.7529.75 C₁₂₋₁₅ alkyl benzoate Finsolv TN 13.75 13.75 13.75 13.75 13.75PPG-14 butyl ether Fluid AP 8.0 8.0 8.0 8.0 8.0 Stearyl alcohol LanetteC18 Deo. 18.0 18.0 18.0 18.0 18.0 Castor wax MP80 3.5 3.5 3.5 3.5 3.5Polyethylene wax Performalene 400 1.0 1.0 1.0 1.0 1.0 Fragrance Parfum1.0 1.0 1.0 1.0 1.0 SWR (%) vs. A +31 +27 +14 −7 0

Sweat Weight Reduction (SWR) results were obtained for each Example indirect comparison with a standard AZAG stick product (ComparativeExample A) using a test panel of 30 female volunteers. Test operatorsapplied ca. 0.3 g of Example 1, 2, 3, or 4 to one axilla and ComparativeExample A (ca 0.3 g) to the other axilla of each panellist. 1 Preparedas described above.

This was done once each day for three days for each comparison. Afterthe third application, panellists were requested not to wash under theirarms for the following 24 hours. 24 hours after the third and finalproduct application, the panellists were induced to sweat in a hot-roomat 40° C. (±2° C.) and 40% (±5%) relative humidity, for 40 minutes.After this period, the panellists left the hot-room and their axillaewere carefully wiped dry. Pre-weighed cotton pads were then applied toeach axilla of each panellist and the panellists re-entered the hot-roomfor a further 20 minutes. Following this period, the pads were removedand re-weighed, enabling the weight of sweat generated to be calculated.

The SWR for each panellist was calculated as a percentage (% SWR) andthe mean % SWR was calculated according to the method described byMurphy and Levine in “Analysis of Antiperspirant Efficacy Results”, J.Soc. Cosmetic Chemists, 1991 (May), 42, 167-197.

From the results in Table 1 it can be seen that the stick with 25% AASCH(Example 2) gave a SWR reduction that was 27% greater than the standardAZAG stick product, a remarkable result. Also, a stick with only 17.5%AASCH (Example 3) gave a SWR reduction that was marginally better thestandard AZAG stick product.

The soft solid compositions detailed in Table 2 (Examples 5 to 9) may beprepared using the same AASCH as used for Examples 1 to 4, using methodsknown in the art.

TABLE 2 Examples 5 to 9 Example Chemical name 5 6 7 8 9 AASCH 28.0 26.3  25.0  20.0  20.0  Cyclopentasiloxane To 100 To 100 To 100 To 100To 100 Silicone elastomer¹ 4.0 4.0 4.0 4.0 4.0 Fumed silica 1.0 1.0 1.01.0 1.0 Dimethicone — 5.0 — 5.0 10.0  (350 mPa.s) PPG-14 butyl ether10.0  5.0 — — — C₁₂₋₁₅ alkyl benzoate — — 10.0  5.0 — Sunflower seed oil0.5 0.5 0.5 0.5 0.5 Microcrystalline wax 3.5 3.5 3.5 3.5 3.5 (MP 80-87°C.) Paraffin wax 3.5 3.5 3.5 3.5 3.5 (MP 60-62° C.) Fragrance 0.8 0.80.8 0.8 0.8 ¹DC9040, ex Dow Dorning. 70-90% Cyclopentasiloxane.

1. An anhydrous antiperspirant stick or soft solid compositioncomprising an antiperspirant active system, thickening agent, andnon-aqueous carrier oil, characterised in that the particulateantiperspirant active system is composed of a water soluble calciumsalt, an amino acid and an aluminium sesquichlorohydrate of formulaAl₂(OH)_(4.7)Cl_(1.3) to Al₂(OH)_(4.9)Cl_(1.1) heat activated with awater soluble calcium salt and an amino acid, wherein the aluminiumsesquichlorohydrate in the antiperspirant active system has a molarratio of calcium to aluminium of at least 1:20 and a molar ratio ofamino acid to aluminium of at least 1:10 and wherein the particulateantiperspirant active system has a mean particle size (D50) of from 2 to30 microns, wherein the antiperspirant active system is present in aconcentration of 10% to 25%, by weight of the composition, and whereinthe amino acid is glycine.
 2. (canceled)
 3. Ah composition according toclaim 1, wherein the aluminium sesquichlorohydrate in the antiperspirantactive system has a Band III content of at least 40%.
 4. The compositionaccording to claim 1, wherein the aluminium sesquichlorohydrate in theantiperspirant active system has a molar ratio of calcium to aluminiumof at least 1:15 and the molar ratio of amino acid to aluminium of atleast 1:4.
 5. The composition according to claim 1, wherein the watersoluble calcium salt is calcium chloride.
 6. (canceled)
 7. Thecomposition according to claim 1, wherein the aluminiumsesquichlorohydrate in the particulate antiperspirant active system hasa Band III to Band II ratio of 5:1 or greater.
 8. A method ofmanufacture of an antiperspirant composition according to claim 1,wherein a solution of aluminium sesquichlorohydrate of formulaAl₂(OH)_(4.7)Cl_(1.3) to Al₂(OH)_(4.9)Cl_(1.1) is heated with a watersoluble calcium salt to achieve a Band III content of at least 40%before being spray dried to give a powder which is subsequentlyformulated with thickening agent and non-aqueous carrier oil to give acomposition having a penetration force value of at least 500 gram-force,wherein both calcium and amino acid are present and the molar ratio ofcalcium to aluminium is at least 1:20 and the molar ratio of amino acidto aluminium is at least 1:10.
 9. The method according to claim 8,wherein the solution of aluminium sesquichlorohydrate of formulaAl₂(OH)_(4.7)Cl_(1.3) to Al₂(OH)_(4.9)Cl_(1.1) is heated with a watersoluble calcium salt and an amino acid to achieve a Band III content ofat least 60% before it is spray dried.
 10. The method according to claim8, wherein the water soluble calcium salt is calcium chloride. 11.(canceled)
 12. The composition according to claim 1 wherein theparticulate antiperspirant active system has a mean particle size (D50)of from 2 to 10 microns.
 13. The composition according to claim 1wherein the composition is in the form of an anhydrous antiperspirantstick.